Pressure-operated mechanism



Oct. 12, 1965 F. PLASSER ETAL 3,211,064

PRES SURE-OPERATED MECHANI SM Filed Nov. 19, 1964 7 INVENTORS Elli L $45513 $99: (Mu/flak United States Patent 3,211,064 PRESSURE-OPERATED MECHANISM Franz Plasser and Josef Theurer, both of .lohannegasse 3, Vienna I, Austria Filed Nov. 19, 1964, Ser. No. 412,563 Claims priority, application Austria, Nov. 29, 1963, A 9,599/63 3 Claims. (Cl. 91411) The present invention relates to pressure-operated mechanism for varying the relative distance between two a-djacently mounted tools. More particularly, it is designed for conventional track tamping machines with pairs of cooperating tamping tools whose relative distance is varied for tamping ballast underneath track ties.

Track tampers of this type wherein vibratory tamping tools are hydraulically opened and closed, i.e. the tools of each pair of cooperating tools are moved together for tamping and moved apart after tamping is completed, are well known and fully described and illustrated, for instance, in our US. Patent No. 2,876,709. In the known hydraulic motors for varying the relative distance of tamping tools, use is made of valve systems and other control elements for operating the hydraulic motors for opening and closing movement of the tools. Thus, the pressure-operated mechanism comprises two hydraulic motors connected to respective ones of the tools, a source of hydraulic fluid, conduit means connecting each hydraulic motor to the hydraulic fluid source, and adjustable valve means in the conduit means for selectively supplying hydraulic fluid from the source to the hydraulic motors and for permitting the fluid to flow out of the motors back to the source.

It is the primary object of the present invention to simplify the pressure fluid operation of the tamping tool movement and thus to reduce possible sources of breakdown in the mechanism whereby the useful life of the mechanism is correspondingly increased.

It is another object of this invention to facilitate the assembly and dismounting of the mechanism.

The above and other objects and advantages are accomplished in accordance with the invention in a mechanism of the described type by using, for the moving apart of the tools, a fluid pressure-operated means mounted between the tools and connected thereto for maintaining the tools at a distance, and a source of pressure fluid supplying the pressure-operated means with pressure fluid under a substantially constant pressure. This constant pressure source is used for moving the tools apart, instead of the conventional valve-controlled pressure means, the pressure of the hydraulic fluid supplied to the hydraulic motors exceeding the constant pressure and moving the tools towards each other when the hydraulic fluid is supplied to the hydraulic motors, and the constant pressure moving the tools apart when the hydraulic fluid is permitted to flow back to its source.

The constant pressure source is a conventional fluid reservoir or blast box wherein a substantially constant fluid pressure is maintained automatically at a given level, pump means being provided for equalizing any pressure changes which may occur temporarily. Such fluid pressure reservoirs are well known and require no further description.

The manufacture and assembly of such a mechanism is particularly simple because the cylinder and piston members of the hydraulic motors as well as the fluid pressure-operated means may be readily assembled and disassembled without the necessity of removing other parts of the machine.

The above and other objects, advantages and features of the present invention will become more apparent in 3,211,064 Patented Oct. 12, 1965 the light of the following detailed description of a preferred embodiment, taken in conjunction with the single figure of the accompanying drawing showing a cross section of the pressure-operated mechanism of this invention.

The invention is shown applied to the conventional vibratory tamping tools of a track tamper, as described and illustrated, for instance, in our US. Patent No. 2,876,709. Since all but the driving mechanism for the tamping tools is conventional and may take the form of the US. patent, if desired, the structure of the tamper is not further described or illustrated, except inasmuch as it cooperates with the mechanism of the invention. Thus, there are indicated the tool holders 1 carrying tamping jaws 2 which, in a manner not shown and well known, are arranged to be immersed in the ballast adjacent a tie. When the tamping jaws are so immersed, the tamping tools are vibrated and moved towards each other to compact or tamp the ballast underneath the tie. Vibration is effected by means of a cam shaft 4 which, upon rotation, imparts a reciprocating or vibratory motion to the tamping tool mounting arms 3, 3 which are linked to one of the ends of the tamping tools, as is well known and fully described, for instance, in the above patent. The mounting arms interconnect the tools at one of their ends to maintain these ends at a fixed distance.

As is also known, the pairs of tamping tools are mounted on a tamping tool carrier 7 which is moved up and down on the tamper machine frame to immerse thetamping tool jaws in the ballast and remove them therefrom during forward movement of the tamper on the track. A pair of parallel guide rods 5, 6 are mounted on carrier 7 and support the tools for glidable movement on the rods when their relative distance is varied.

The pressure-operated mechanism for varying the relative distance between the two adjacently mounted tools comprises a pair of like hydraulic motors 9, 10 and a fluid pressure-operated means 19, 20 connected to respective ones of the tools. A means is provided for linking each tool at a point intermediate its ends to the hydraulic motors and to the fluid pressure-operated means, respectively, this means being illustrated as a connecting piece 8 which is attached to the associated tool by pivotal connection 8.

The illustrated hydraulic motors each comprise a stationary cylinder member 1t and a piston member 9 gliding in the cylinder member. In the illustrated embodiment, the piston member is fixed to, or integral with, connecting piece 8 but it will be obvious that this may be reversed and the cylinder member may be movable with the connecting piece while the piston member is fixedly mounted on carrier 7, the cylinder and piston members always being glidable relative to each other.

A source of hydraulic fluid shown as hydraulic fluid storage tank 15 is connected to each hydraulic motor by suitable conduit means illustrated at 11. An adjustable valve means 12 is arranged in the conduit means for selectively supplying hydraulic fluid from tank 15 to the hydraulic motors and for permitting fluid to flow out of the motors back to the tank. The illustrated hydraulic fluid delivery system includes a pump 14 whose input is connected to the tank 15 and whose output 13 leads to valve 12.

When the valve is adjusted in the illustrated position, pump 14 delivers hydraulic fluid to the valve which directs it back to the tank through return conduit 16. Meanwhile, any hydraulic fluid displaced out of the hydraulic motors is permitted to flow back into the storage tank through valve 12 and return conduit 17. A pressure-relief valve 18 is mounted in a branch conduit connecting return conduit 17 and delivery conduit 11 to set the maximum limit of pressure in conduit 11 and prevent excessive pressure from being applied to the tamping tools.

The fluid pressure-operated means illustrated herein also comprises a cylinder member and a piston member gliding in the cylinder member, the cylinder member 19 being fixed to, or integral with, one of the connecting pieces 8 while the piston member 20 is fixed to, or integral with, the other connecting piece 8. As shown, this fluid pressure-operated means is mounted between the tools and maintains the same at a distance determined by the constant pressure supplied to cylinder member 19. For this purpose, there is provided a conventional pressure fluid storage device 21 constituting a source of pressure fluid supplying pressure fluid to cylinder 19 under a substantially constant pressure through conduit 22. The pressure fluid may be air, another suitable gas or a suitable fluid.

When valve 12 is adjusted so that conduit 13 communicates with conduits 11, While the latter conduits are out of communication with return conduits 16 and 17, the hydraulic pressure in the hydraulic motors exceeds the constant pressure in cylinder 19 so that the tools are moved towards each other. When the valve 12 is in the illustrated position, the constant pressure in cylinder 19 will move the tools apart and displace the hydraulic fluid in cylinders 10, 10, the displaced fluid being permitted to flow back to tank 15 through conduits 11 and 17.

It will be noted that, in the illustrated embodiment, the transverse cross sectional area of the piston members 9, 9, exceeds that of the piston member 20, which further increases the pressure diflerential between the hydraulic motors, on the one hand, and the pressure fluid-operated means 19, 20, on the other hand. Thus, when hydraulic fluid is supplied to the hydraulic motors, they move the tools together against the constant pressure in cylinder 19 until the maximum pressure regulated by pressure-relief valve 18 is attained in the hydraulic motors or until the valve is adjusted to assume its illustrated position. The connecting pieces 8 are held by the counter-pressure in cylinder 19 against undesirable vibration during the closing movement of the tools.

While the present invention has been described and illustrated in connection with a now preferred embodiment, it will be understood that many modifications and variations may occur to those skilled in the art, particularly after benefiting from this teaching, without departing from the spirit and scope of the invention as defined in the appended claims.

We claim:

1. A pressure-operated mechanism for varying the relative distance between two adjacently mounted tools, comprising two hydraulic motors connected to respective ones of said tools, a source of hydraulic fluid, conduit means connecting each hydraulic motor to said hydraulic fluid source, adjustable valve means in said conduit means for selectively supplying hydraulic fluid from said source to said hydraulic motors and for permitting said fluid to flow out of said motors back to said source, a fluid pressure-operated means mounted between said tools and connected thereto for maintaining said tools at a distance, and a source of pressure fluid supplying said pressureoperated means with pressure fluid under a substantially constant pressure, the pressure of the hydraulic fluid supplied to the hydraulic motors exceeding said constant pressure and moving said tools towards each other when the hydraulic fluid is supplied to the hydraulic motors, and the constant pressure moving the tools apart when the hydraulic fluid is permitted to flow back to said firstnamed source,

2. The pressure-operated mechanism of claim 1, further comprising a carrier for said tools, a pair of parallel guide rods mounted on said carrier and supporting said tools for glidable movement on said rods, means interconnecting the tools at one of their ends to maintain said ends at a fixed distance, and means for linking said tools at points intermediate their ends to said hydraulic motors and said fluid pressure-operated means, respectively.

3. The pressure-operated mechanism of claim 1, wherein each of the hydraulic motors comprises a cylinder member and a piston member in said cylinder member said members being glidable relative to each other, each tool being linked to one of said members of each motor, the fluid pressure-operated means comprises a cylinder member and a piston member gliding in the latter cylinder member, one of said latter members being linked to one tool and the other one of said latter members being linked to the other tool, and the transverse cross sectional area of the piston members in said hydraulic motors exceeding the transverse cross sectional area of the piston member in said fluid pressure-operated means.

References Cited by the Examiner UNITED STATES PATENTS 1,460,586 7/23 Howse 60-52 X 2,483,239 9/49 Sharpe 9275 X 2,876,709 3/59 Plasser et al. 104-12 EDGAR W. GEOGHEGAN. Primary Examiner, 

1. A PRESSURE-OPERATED MECHANISM FOR VARYING THE RELATIVE DISTANCE BETWEEN TWO ADJACENTLY MOUNTED TOOLS, COMPRISING TWO HYDRAULIC MOTORS CONNECTED TO RESPECTIVE ONES OF SAID TOOLS, A SOURCE OF HYDRAULIC FLUID, CONDUIT MEANS CONNECTING EACH HYDRAULIC MOTOR TO SAID HYDRAULIC FLUID SOURCE, ADJUSTABLE VALVE MEANS IN SAID CONDUIT MEANS FOR SELECTIVELY SUPPLYING HYDRAULIC FLUID FROM SDAID SOURCE TO SAID HYDRAULIC MOTORS AND FOR PERMITTING SAID FLUID TO FLOW OUT OF SAID MOTORS BACK TO SAID SOURCE, A FLUID PRESSURE-OPERATED MEANS MOUNTED BETWEEN SAID TOOLS AND CONNECTED THERETO FOR MAINTAINING SAID TOOLS AT A DISTANCE, AND A SOURCE OF PRESSURE FLUID SUPPLYING SAID PRESSUREOPERATED MEANS WITH PRESSURE FLUID UNDER A SUBSTANTIALLY CONSTANT PRESSURE, THE PRESSURE OF THE HYDRAULIC FLUID SUPPLIED TO THE HYDRAULIC MOTORS EXCEEDING SAID CONSTANT PRESSURE AND MOVING SAID TOOLS TOWARDS EACH OTHER WHEN THE HYDRAULIC FLUID IS SUPPLIED TO THE HYDRAULIC MOTORS, AND THE CONSTANT PRESSURE MOVING THE TOOLS APART WHEN THE HYDRAULIC FLUID IS PERMITTED TO FLOW BACK TO SAID FIRSTNAMED SOURCE. 